Manufacture of isodibenzanthrones



Patented Oct. 11, 1927. 1

UNITED STATES PATENT OFFICE.

-TO I. G.

FARBENINDUSTRIE AKTIENGESELLSCHAFT, OF FRANKFORT-ON-THE- MAIN, GERMANY,A CORPORATION OF GERMANY.

MANUFACTURE OF ISODIBENZANTHRONES.

No Drawing. Application filed February 9, 1926, Serial No. 87,167, andin Germany February 16, 1925.

I have found'that isodibenzanthrones can be prepared in an advantageousmanner by treating mixtures of B2 l-benzanthrone-thioethers andbenzanthrones not substituted in 5 the B2 1position both componentshaving a free 2-position with alkaline condensing agents. Generally,about equimolecular quantities of the two components will be employed,but the process is not limited to a certain proportion of thecomponents. Mixtures of caustic alkalis with alcohols are especiallysuitable as condensing agents. It is advantageous to exclude oxygenduring the condensation as far as possible, for

example by introducing an inert or reducmg gas.

The following example will further illustrate my invention which,however, is not limited to this example. The parts are by weight.

Emample.

A mixture of 17.6 parts of benzanthrone- Bz l-thioaracresyl-ethercorresponding to the formu a and 11.5 parts of benzanthrone areintroduced into a solution of parts of sodium in 500 parts of water-freeethyl alcohol -heated to about 105 to 110 degrees centigrade whiledistilling off part of the alco- 49 hol, and kept at the saidtemperature for some hours while stirring. The isodibenzanthrone soprepared can be separated and purified in the usual manner. It isobtained rically or asymmetrically substitute in a considerably betteryield and, owing to the use 1n part of simple benzanthrone, 5

at a lower cost than when treating benzan- (see Scholl, Ber. d.Deutschen Chem. Gesellsch., vol. 55, p. 114) amono-chlor-isodibenzanthrone is obtained. Other s mmti: 1sobenzanthrones may be prepared in an analogous way.

What I claim is:

1. The process of manufacturing isodibenzanthrones which consists intreating a mixture of a benzanthrone-Bz l-thio-ether having a free2-position and a benzanthrone with free 2- and Bz l-positions with analkaline condensing agentsubstantially in the absence of oxygen.

2. The process of manufacturing isodibenzanthrones which consists intreating a mixture of about equimolecular proportions of abenzanthrone-Bz l-thio-ether having a free 2-position and a benzanthronewith free 2- and Bz l-positions with an alkaline con- 30 densing agentsubstantially in the absence of oxygen.

In testimony whereof I have hereunto set my hand.

HEINRICH NERESHEIMER.

EERTKFHGATE 0h CURRECTIGN.

Patent No. L64 2q85ii, Granted (Detober 11, 1927, to

HEENR ii (Si-i NERESHEIMER.

It is hereby certiiieti that the above numbered patent wee erroneouslyissued to "l. G. Farhenindnstrie Aktiengeseiischei't, ofFrankiort=on-the-Main, Gertnnny a Uorporation oi Germany", whereas saidpatent should have been issued to "Gresseiii Dyeetnfi Corporation, oiNew York N. Y., a Corporation of Delawere" saioi Corporation beingnssignee by mesne assignments of the entire interest in said? invention,as shown by the records of assignmentsin this office; and that the saidLetters Patent shoniri be read with this correction therein that thesame may conform to the record of the case in the Patent Office.

Signed and sealed this 8th day of November, A. D. 1927.

" Ma Moore,

Seal. Acting Commissioner oi Pntenten

